battery cable routing question.

I'm trying to simplify my battery cable connections. I wanted to ask before I did anything stupid. I want reroute my positive alternator connection straight to the starter and from the starter to the positive on the battery.

How bad of an idea is this?

 

Why though, I wouldn't touch it. You're just creating more points of failure.

But if you really wanted to, maybe @mechanicjon is better suited to answer this.

 

I'm assuming a 4cyl. I guess you could but it does create more connections for failure points.

 

On a 4cylinder the starter already goes straight to the battery, alternator runs into the fuse block and straight through the fuse out to the battery. The connections are already direct, they don't loop through anything so you don't necessarily gain anything from swapping them out.

If you're doing it because you're upgrading your alternator to put out more amps you can swap out the wiring for larger gauge and get a larger capacity fuse for the stock location.

 

I should add though, if you wanted to pull the harness out and take it apart they can be re-loomed to make everything much cleaner and eliminate the big ugly wire clamp that bolts to the motor mount.

 

Hey Flippy.....On my 3.4 I ran a 4gauge cable from the positive terminal on the starter to the positive terminal on the battery. I did leave the factory wiring in place.
In my mind, I was expecting it turn over faster, but I really don't notice any difference.
Also did the following:
4gauge cable from the negative terminal on the battery to the where the alternator bolts to the block
4gauge cable from the negative terminal on the battery to the frame (just to the right of the battery where the small factory ground wire is typically located)
4gauge cable from the back of the motor to the firewall (again, replacing the small gauge wire)
4gauge cable from the alternator directly to the battery, with an inline fuse. Again, I know it's still going through the fuse box and it's not the most ideal set up, but I didn't want to disturb the factory wiring.

When the time comes to replace the factory alternator, I'm considering going the GM alternator swap. 120 amp idle / 140 amp at highway speed.

https://www.tacomaworld.com/threads/140-amp-cadillac-deville-alternator-swap-observations.206153/

My Tacoma does what I've seen many comment on. With the lights running, fan blower on, the idle drops really low. I've got a voltmeter and done the test at battery, etc., and everything is within specs.
It seems the only way to improve the situation is to upgrade the alternator.

 

I've upgraded the cables to 1/0 gauge, one from alternator to battery, one from starter to battery, and a 4 gauge wire to the fuse box. I'm trying to work in a second battery and clean up extra cables I could

 

It seems fine now just melted some plastic

Gonna make it safer this weekend

 

Are you going to put a fuse between alternator and starter? If you don't put that protection you may set your truck on fire when alternator fails. There are two positive wires going to alternator:
1 fat wire that that goes to fuse box and via 120A fuse it connects to battery. 1 thin wire that goes to fuse box and via 7.A fuse is connected to fat alternator wire. The second wire is powering "charging coil".
There are other two wires used for regulator module that you still need to deal with.

I don't see how you can make ti simpler without bypassing required fuses.

 

I thought so...

I'm trying to figure out how to clean up my battery cables. I've got a 1/0 awg wire from alternator to fuse to battery, and 1/0 awg from starter to battery, and a 4 awg wire coming from battery to 80amp fuse in the fuse box.

I'd like to run a third cable to a second batter, but the cables are getting kinda crowded.

 

What kind of battery terminals are you running? Swapping those out to aluminum car audio terminals can make a huge difference.

https://toolmakermetalworkz-com.myshopify.com/

All kinds of different options and you can make it cleaner and route cables at different angles. Just something to think about if you're after installing a lot of electrical stuff.

 

That's a weird setup. Why the alternator runs to the battery? It does not make sense. If you upgraded the alternator to provide more power it should be wired the same as original meaning the power wire from the alternator to fuse box and change the main fuse from 80A to whatever your upgraded alternator can handle. By the way the power wire from alternator does not need to be that thick. Voltage drop does not play any role here as it is regulated from the voltage at the fuse box anyway. It should be sized to main fuse size.

So you should have only two positive wires at the battery: unfused to starter and the second wire (sized to man fuse) to fuse box.

If you want to run additional fuse box for add-on accessory power (compressor, fridge, lighting etc.) than it needs to be connected to the battery (via another main fuse), so then you will have additional positive wire to the battery. Adding secondary battery is additional setup, and wiring depends how it is going to be used (as a backup battery or aux battery).

 

I've ordered new wire and I'm going to 4 AWG all around, for the alternator, to fuse box, fuse box to battery positive and battery positive to starter. I'm changing the grounds to 4 AWG as well.

This should clean things up and I've definitely learned my lesson.